Omega-3 fatty acid oils possess properties that can be used for numerous therapeutic advantages, including treatment of autoimmune and inflammatory diseases such as rheumatoid arthritis, psoriasis, inflammatory bowel diseases such as Crohn's disease and ulcerative colitis; immunosuppressive treatment; hypertension prophylaxis in normal humans and in heart transplant patients; coronary heart disease; hyperlipidemia; hypertriglyceridemia; improvement of renal function and nephrotoxicity reduction. U.S. Pat. No. 4,678,808 describes the use of these oils to treat disorders associated with arachidonic acid metabolites, including autoimmune syndromes, acute and chronic inflammatory diseases, atherosclerosis, stroke, myocardial infarction, deep vein thrombosis, surgery, hyperlipidaemic states, hypertension, enhanced platelet responsiveness, vascular lesions and occlusions, vascular spasm and diabetes. According to U.S. Pat. No. 5,225,441, which describes compositions for treating gingivitis and periodontitis, omega-3 polyunsaturated fatty acids compete with omega-6 polyunsaturated fatty acids as a substrate in the arachidonic acid cascade and can therefore alter the synthesis of prostaglandin and leukotrienes, both of which are powerful mediators of inflammation and immune response. Other uses of omega-3 fatty acid oils are described in U.S. Pat. No. 5,034,415 (diabetes mellitus), U.S. Pat. No. 4,843,095 (rheumatoid, arthritis), JP 2253629 (anticancer), U.S. Pat. No. 4,879,312 (enhancing angiogenesis), JP 1290625 (improvement of cerebral function), EP 378,824 (anti-cachexia, cholesterol and triglyceride levels reduction, platelet aggregation inhibition, colon adenocarcinomas growth inhibition), U.S. Pat. No. 5,457,130 (cancer cachexia, malignant tumors, abnormal cAMP levels in adipose tissue, lipolytic activity inhibition) and U.S. Pat. No. 5,436,269 (hepatitis).
Cyclosporins are an example of a class of drugs that is soluble in omega-3 fatty acid oil and capable of exerting an additive or synergistic therapeutic effect with the omega-3 fatty acid oil. Alternatively, the omega-3 fatty acid oil mediates the negative side effects, such as nephrotoxicity, of a cyclosporin such as cyclosporin A.
Cyclosporin A (CyA) is a lipophilic cyclic undecapeptide that can be isolated from the fungus Tolypoclodium inflatum Gams and which produces calcium dependent, specific and reversible inhibition of transcription of interleukin-2 and several other cytokines, most notably in T helper lymphocytes. Because of its immunosuppressive properties, it is widely used as first line therapy in the prophylaxis and treatment of transplant rejection (e.g., allo- or xeno-transplant rejection such as in patients receiving heart, lung, combined heart-lung, liver, kidney, pancreatic, skin or corneal transplants) and various autoimmune and inflammatory diseases. CyA is used in the treatment of multi-drug resistance syndrome, for example in patients undergoing chemotherapy or following organ transplantations. In patients with severe disease refractory to standard treatment; CyA is an effective therapy in acute ocular Behcet's syndrome; endogenous uveitis; psoriasis; atopic dermatitis; arthritis, particularly rheumatoid arthritis; active Crohn's disease and nephrotic syndrome. Other conditions include arthritis chronica progrediente and arthritis deformans, autoimmune hematological disorders including hemolytic anemia, aplastic anemia, pure red-cell anemia and idiopathic thrombocytopenia, systemic lupus erythematosus, polychondroitis, scleroderma, Wegener granulamtosis, dermatomyositis, chronic active hepatitis, myasthenia gravis, Steven-John syndrome, idiopathic sprue, autoimmune inflammatory bowel disease, e.g., ulcerative colitis, endocrine ophthalmology, Graves disease, sarcoidosis, multiple sclerosis, primary biliary cirrhosis, juvenile diabetes, keratoconjunctivitis sicca and vernal keratoconjunctivitis, interstitial lung fibrosis, psoriatic arthritis, glomerulonephritis, juvenile dermatitis, asthma, tumors, hyperproliferative skin disorders and fungal infections. This drug has also been used to treat patients with moderate or severe aplastic anemia who are ineligible for bone marrow transplantation and those with primary biliary cirrhosis. CyA may be effective in patients with intractable pyoderma gangrenosum, polymyositis/dermatomyositis or severe, corticosteroid-dependent asthma. CyA is known to have a very specific effect on T-cell proliferation although the precise mechanism remains unclear. A number of non-immunosuppressive analogues of cyclosporin A have been shown to have resistance modifier activity and some are more potent than the parent compound. Nephrotoxicity, hepatotoxicity, hypertension, headache, hypertrichosis, gingival hyperplasia, neurological and gastrointestinal effects, thrombocytopenia and microangiopathic hemolytic anemia, hyperkalemia and hyperuricemia and development of skin and lymphoproliferative malignancies are the most common adverse events in cyclosporin recipients.
CyA and fish oils have been administered concurrently to organ transplant patients in various clinical trials. For instance, Andreassen et al. (JAAC, 29(6): 1324-31 (1997) reported effective hypertention prophylaxis in heart transplant patients who were given cyclosporin A and 4 g of fish oil. Cyclosporin A-treated and fish oil fed renal transplant recipients had improved renal function following a rejection episode (Transplantation, 54:257 (1992)). U.S. Pat. No. 5,118,493 describes the administration of CyA together with an omega-3 fatty acid oil to mediate the nephrotoxic effects of the cyclosporin.
Certain oil mixtures of lipophilic drugs such as a cyclosporin with vegetable oils or other lipidic substances, surface active agents, solvents and other excipients are known to spontaneously produce dispersions of very low mean particle size (such as&lt;200 nm) when mixed with an aqueous medium. These dispersions are known as microemulsions and the oily mixtures that produce the microemulsions are popularly referred to as microemulsion preconcentrates. Upon oral delivery, the microemulsion preconcentrates are thought to produce similar dispersions of very low particle size with gastric and other physiological fluids.
Cyclosporins are highly lipophilic, poorly water soluble and, therefore, have been supplied as an olive oil or peanut oil solution for clinical use. However, the bioavailability of cyclosporin from such oily solutions is very low and gives rise to great intersubject variation with reported systemic availability ranging from 4 to 25% (Takada, K. et al, J. Pharmacobio-Dyn., 11:80-7 (1988)). The bioavailability of cyclosporin has been reported to be dependent on food, bile and other interacting factors (Clin. Pharmacokinetics, 24:472-95 (1993)). A widely used commercial formulation of CyA, SANDIMMUNE.RTM. for oral administration, is a solution of cyclosporin A in vegetable oil derivatives containing some other inactive excipients. Very high inter- and intra-patient and food dependent variability in the bioavailability of CyA has been observed from this formulation. The commercial microemulsion preconcentrate formulation, NEORAL.RTM., has been claimed to provide high bioavailability for CyA with low inter-and intra-patient variability. However, risks of adverse drug reactions have been indicated on switching to Neoral.RTM. (see, e.g., Drug Saf, 16:366-73 (1996); Lancet, 348:205 (1996)).
Numerous microemulsion preconcentrate formulations are known, including soft gel formulations, for enhancing the solubilization and oral bioavailability of a poorly water soluble drug compound such as cyclosporine. Typically, these formulations include an active agent, an oil component, a surfactant to emulsify the formulation and a hydrophilic solvent/co-surfactant system to solubilize the active agent. Typical solvent/co-surfactant systems include ethanol, polyethylene glycols, propylene carbonate, dimethylisosorbide, Transcutol and/or Glycofurol. Disadvantages of these formulations include stability or precipitation problems caused by migration of volatile hydrophilic solvents or cosolvents (e.g., ethanol can permeate a gelatin shell at normal storage temperatures), stability or precipitation problems caused by hygroscopic solvents or co-surfactants (e.g., propylene glycols, Transcutol, Glycofurol), and toxicity problems caused by addition of certain solvents or co-surfactants (e.g., dimethylisosorbide).
Typically, the oil component of a conventional microemulsion consists of fatty acid mono-, di- or triglycerides from a vegetable oil; medium chain triglycerides and/or mono- or di-glycerides; mixtures of glycerides and polygycolized glycerides; tocol, tocopherols, and/or tocotrienols; or hydrophobic alcohols. U.S. Pat. No. 5,603,951 describes a microemulsion concentrate containing cyclosporin as an active ingredient, dimethylisosorbide as a required co-surfactant, a surfactant, and an oil which can be refined fish oil, these components being present in the ratio of 1:1-5:2-10:1-5. The inventors of the '951 patent added dimethylisosorbide, which is a solvent available under the Tradename ARLASOVE.RTM., to the formulation to address the disadvantages listed above for prior solvents/co-surfactants systems such as ethanol, Transcutol, or Glycofurol. The '951 preconcentrates are formed by dissolving the cyclosporin in the dimethylisosorbide at a temperature of approximately 60.degree. C. followed by addition of the oil component and the surfactant.
It is an object of the present invention to provide a stable, self-emulsifying microemulsion or emulsion preconcentrate formulation and/or a microemulsion or emulsion containing an omega-3 fatty acid oil that is capable of enhancing the bioavailability of a poorly water soluble therapeutic agent while minimizing the inter- and intra-patient or food variability in the bioavailability of the therapeutic agent. A further object is to provide self-emulsifying preconcentrates or corresponding microemulsions and emulsions having increased therapeutic agent dosing reproducibility compared to conventional formulations. An additional object is to provide self-emulsifying preconcentrates or corresponding microemulsions or emulsions containing an omega-3 fatty acid oil and a poorly water soluble therapeutic agent in which the bioavailability and dosing reproducibility of both the omega-3 fatty acid oil and the therapeutic agent is high.
It is an additional object of this invention to provide a stable self-emulsifying microemulsion or emulsion preconcentrate formulation and/or a microemulsion or emulsion in which the omega-3 fatty acid oil and the therapeutic agent exert an additive or synergistic therapeutic effect or the omega-3 fatty acid oil mediates the negative side effects of the therapeutic agent.
A further object of this invention is to provide a stable self-emulsifying preconcentrates and/or a microemulsion or emulsion in which the poorly water soluble therapeutic agent is substantially soluble in the omega-3 fatty acid oil, thus eliminating or drastically reducing the need for substantial amounts of a hydrophilic solvent system.
A further object of this invention is to provide a stable self-emulsifying microemulsion or emulsion preconcentrate formulation and/or a microemulsion or emulsion containing an omega-3 fatty acid oil and a poorly water soluble therapeutic agent which is suitable for formulation into soft or hard capsules for oral administration.
A still further object of this invention is to provide a stable self-emulsifying microemulsion or emulsion preconcentrate soft or hard capsule formulation containing an omega-3 fatty acid oil and a poorly water soluble therapeutic agent having relatively high therapeutic amounts of both the omega-3 fatty acid oil and the poorly water soluble therapeutic agent.